The invention relates to a hermetically sealable container (1) for liquids comprising a container body (10), and a cap (20), configured to close the mouth (13) of the container body (10) and achieve a hermetic seal therewith. The cap (20) comprises a main gripping body (21), and a coupling appendage (22), which is intended to be inserted inside the container body (10) through the mouth (13). The inner surface (110) of a tubular container wall (11) comprises: a conical guide surface (111); an intermediate surface (112) that connects said conical guide surface (111) to a shoulder (113). The intermediate surface (112) defines a first annular prominence (115) in the vicinity of said shoulder (113). The coupling appendage (22) of said cap (20) is dimensioned so that it may be in contact with a head end (221) against said shoulder (113) so as to create a first sealing zone (T1). The head end portion (221) of the coupling appendage (22) is radially dimensioned so that when the head end (221) abuts against said shoulder (113), the head end portion (221) interferes with said first annular prominence (115), creating a second sealing zone (T2) between the cap (20) and the container body (10). The coupling appendage (22) of said cap (20) comprises a second annular prominence (233) which protrudes from said lateral coupling surface (23) near the base (220) of said coupling appendage (22) and is positioned axially so that, when the head end (221) abuts against said shoulder (113), said second annular prominence (222) interferes with the conical guide surface (111), creating a third sealing zone (T3) between the cap (20) and the container body (10).